LOS ANGELES — A cruise ship docked in California on Sunday after 172 people on board fell ill with the highly contagious norovirus during a nearly monthlong trip, the Centers for Disease Control and Prevention said.

Some of the more than 4,100 people aboard the Crown Princess began to show signs of the gastrointestinal sickness a few days into the voyage from Los Angeles to Hawaii to Tahiti.

The ill passengers and crew members were treated on the ship.

A CDC official was expected to board the ship to investigate the outbreak and the cruise line’s response.

The ship will undergo a deep cleaning at a terminal in San Pedro before embarking on its next voyage to the Mexican Riviera, company spokeswoman Susan Lomax said.

In April, 129 people on the same ship contracted norovirus during a seven-day cruise off the California coast. Lomax said that the ship went through the same stringent disinfecting process after it docked.

“As it is the cold and flu season, when the stomach flu circulates on land, we encourage all of our guests to be diligent in following the widely accepted practices of frequent hand washing with soap and water and the use of hand sanitizers,” Lomax said.

Symptoms of norovirus include vomiting, diarrhea, fever and body aches. According to the CDC, most people recover within three days.